Continuous process of making white lead and apparatus therefor.



G. ELLIS.

CONTINUOUS PROCESS OF MAKING WHITE LEAD AND APPARATUS THEREFOR.

APPLICATION FILED JULY 5, 1910.

Patented Sept. 5, 1911.

r si ens ra T OFFTQE.

CARLETON ELLIS, OF MONTCLAIR, NEW JERSEY, ASSIGNOR TOELLIS-FOSTER COMPANY,

. A CORPORATION OF NEW JERSEY.

CONTINUOUS PROCESS OF MAKING WHITE LEAD AND APPARATUS THEREFOR.

Specification of Letters Patent. Application filed July 5, 1910.

Patented Sept. 5, 1911.. Serial No. 570,244.

To all whom it may concern:

Be itknown that I, CARLn'roN ELLIS, a citizen of the United .States, residing at Montclair, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Continuous Processes of Making White Lead and Apparatus Therefor, of which the following is a specification.

This invention relates to the process of and apparatus for making white lead, and relates in particular to a process of and apparatus for'manufacturing wh ite lead in a continuous or non-cumulative manner.

The manufacture of white lead by the old Dutch process involves treatment of the metallic lead for a space of two or three months with corroding agents, and on account of the protracted period of time required for the complete corrosion of the lead, together with the labor. involved and finished product, the cost of manufacture of white lead by this process is relatively high. For this reason numerous processes have come into existence which involve the preliminary comminution of the molten metallic lead in some way, and subsequent treatment of the comminuted product with air, carbon dioxid and moisture; sometimes .the making of white lead in a continuous or non-cumulative manner, which makes the operation anautomatic one from the time the lead is introduced into the melting pot up toethe time whenthe finished white lead is ready to be packed for shipment, and=because 10f .this automatic method .of procedure, labor costs are greatly reduced, wear and "tear -.of apparatus is minimized, and :a product :of uniform quality .is secured.

My invention involves melting the lead, preferablyina tankeguipped witha meltin handling the rawv -to the aperture 12.

ing pot and molten lead reservoir, in comminuting the molten lead by means of a jet of compressed air, inert gas, steam or water, collecting the comminuted product, and maintaining it by such means as an extensive conveying system, in contact wit-h air and carbon dioxid and water or steam or both, until the lead has become converted into basic carbonate of lead or hydrated carbonateof lead, corresponding to the accepted formula for white lead, and finally freeing the product from its moisture.

The accompanying drawing will make .clear the manner in which I carry out the present invention, as it illustrates in a diagrammatic way the essential features of operation. These drawings show in section a melting pot and furnace, conveying means, and inlets and outlets for the various reagents employed.

In the drawing, 1 is a reservoir for the molten lead integral with the melting pot 2 partitioned by the wall or dam 3.

4 isa conveying means suitable for transferring pig lead from .the stock room 'to the melting tank 2. y

5 is a fire box or combustion chamber havingthe ash pit 6.

7 is a flue leading from the housing of this furnace to a stack.

8 is an outlet --pipe for the lead reservoir 1, and is equipped with the plug and lever opening and closing means 9.

10 is a shell surrounding the outlet pipe 8 opening into the heating chamber at, one end and having the outlet pipe 11 at the other end, which may be connected with the stack or a suction fan. The outlet pipe 8 narrows at its lower end to form a flattened aperture.

'13 is an atomizing pipe-feed with the valve 14. Although shown in the drawing as directed downward it may be xplaced in any other suitable position with reference 15 is a receiving bin and 16, 17, 18, 19, and .20 are troughs carrying conveying paddles mounted on the shafting 20, 21, 22 and 23-are1inlet pipes connected with the V conveyer .16, while 24,25,526, 27, 28 and 29 are similar indet pipes arranged on-the conveyer :troughs 17 and 18 respectively.

30 and 31 are exhaust pipes.

32 is a'steam .jacket attached to the conveyer 19, having the steam inlet pipe 33 and outlet pipe 34. Thetrough 20 is similarly equipped with the jacket 35, inlet 36 and outlet 37.

38 is an outlet for the finished product.

The operation of the process is as follows :Pig lead is fed into the melting pot 2, and by means of tire directly beneath this pot, is rapidly melted and flows into the lead reservoir 1 where the lead is maintained in a molten condition due to the products of combustion circulating in the space between the reservoir and the housing. The lead in the reservoir is preferably maintained in a supermolten condition Le. at a temperat lre of 400 or 500 degrees above the meRing point. A portion of the hot roducts of combustion are shunted through the annular passage formed by pipe 8 and shell 10 and pass away through the outlet 11. The passage of this hot gas along the exterior of the pipe 8 serves to keep the latter hot and thus to' maintain the lead at the desired degree of fluidity essential for proper comminution or filamentation. The plug attached to the lever 9 1s adjusted to allow a flow of molten lead through the pipe 8. The lead flows out at the aperture 12, where it comes into contact with the filamenting jet produced by the atomizer 13. The atomizmg medium which may be employed depends to some extent ,upon the character of the lead. A hard lead ordinarily requires treatment differing from that needed for soft lead. As stated, compressed air, steam, superheated steam, inert gas or waste products of combustion or water may be employed in the atomizing process. Water tends to produce a rather coarsely granulated lead, while gases or superheated steam more readily yield a finely or filamentous product. Ordinarily I refer to use compressed heated air to pro uce a filamentous product carrying a coating of catalytic oxid of such .a subsequent conversion is rendered very rapid.

Heretofore it has been customary in manufacturing white lead simply by the use of air, water and carbon dioxid, to oxidize and hydrate the lead in one operation, and subsequently to carbonate in a second operation, these operations being of course of an intermittent character. By the present invention it becomes possible to simultaneously hydrate and carbonate, thereby securing a marked diminution in the total time i'eqaiired for the complete conversion of the The filamentous lead produced by the specified method, carrying a coatin of catalytic oxid, goes into the bin 15, and'the eonveyers 20 being put into operation, the filamentous lead 15 carried with constant and thorough agitation along the conveying paddles of the conveyer insures a steam may be admitted by the pipe 26.

divided character that the conveyers prior to drying.

troughs 16, 17, 18, 19 and 20. Through the pipes 21, 22 and 23, air, water and carbon dioxid or air, waterand steam may be admitted. React-ion takes place during the slow travel of the material along the conveyer 16, and the agitation produced by the mingling of the reacting materials. Hydration or hydration and carbonation, as the case may he, sets in. In the conveyer 17 air and carbon dioxid may be introduced by the pipes 24 and 25 respectively, and if desirelcl similar method ofoperation obtains with the inlet pipes 27, 28 -and 29 of the conveyer 18. The waste gases" are drawn out from the conveying system by means of the out lets 30 and 31 which are connected to suetion fan-blowers. I

In order to hasten the operation wien the lead has reached a certain degree of ydration and carbonation, heating of the traveling mass of material may be resorted to, and for this purpose steam is entered into the steam jacket 32 thereby heating the trough 19 fora considerable portion of its length. The proportion of carbon dioxid admitted at this point may be very high and in fact air may be largely excluded- The operation is so conducted that by the time the product reaches the conveyer 20 it has become completely hydrated and carperfect bonated, and during the last portion of its travel 1t is subjected to heat for the purpose of removing moisture.- This is done by entering steam into the jacketed inclosure 35, heated air at the same time if desired being passed through the trough. v,The. dry material discharges at 38 and may be packed for shipment.

With the employment of reagents, such as acetic acid, in connection with hydration and carbonation process above, described the product may be washed after leaving the It will, be evident from the aforegoing that the present process of continuous manufacture mvolvesa great labor saving, and

the opportunity to produce a product of cat uniformity. Furthermore it allows the changes taking place in the transformation of lamentous lead intowhite lead to be carefully watched at every stage and to rmit of modification of the atmosphere bathing the material to give rise to the most complete and ra id conversion.

Having descn' tails of which I what I claim is: I

1. The process of making white lead which consists in melting lead, converting it into a finely divided product and subjecting a continuously, sively advancing stream of said product to the action of air, moisture and carbon diintegrally and progreswhich comprises melting lead, raising it f condition, comminuting and carbon dioxid in the oxid under substantially sure, whereby, said finely divided productis progressively converted-into white lead.

2. The process of making white lead which comprises melting lead, raising it to a supermolten condition,

comminuting by a pressure, jet to make a comminuted lead product and subjecting a continuously, integrally, and progressively advancing" stream of said product to the action of air, moisture and 'carbon dioxid, under substantially 'atmospheric pressure, whereby said finely divided product is progressively converted into white lead. v

3. The process of making white lead which comprises melting lead, raising it to a super-molten condition, comminuting by means of apressure jet containing an oxidizing medium, whereby filamentous lead coated with a catalytic 'oxidis produced and subjecting a continuously, integrally and progressively advancing stream. of said product to the action of-alr, carbonwdioxid under substantially atmospheric pressure, whereby said finely divided product is progressively converted into white lead. 5 r .4. The process of making white lead which comprises raising lead to a temperature of about 400 above its melting point, 'comminutin'g by means of a jet of heated air under high pressure, whereby filamentous lead coated with a catalytic oxid is produced and in subjecting arcontinuously,

integrally and progressively advancing stream of said product to a gaseous current containing oxygen under substantially atmospheric pressure in the presence of moisture to bring about hydration and in converting the product intobasic carbonate of lead by the prolonged faction of oxygen presence of moisture at a temperature above atmospheric, said process being conducted m' a continuously-progressive and non-cumulative man- 5. The process of making white lead,

to a supermolten by means of a pressure jet contammg an oxidizing medium whereby filamentous lead coated with a' catalytic oxid is atmospheric presmoisture and I In testimony signatureinpresenceof two w tnesses.

produced, treating the superficially oxidized lead as it an integral progresslvely-advancing travelby agitation in the presence ing stream of moisture, air and carbon dioxid; whereby the lead product is converted into white lead; and in drying the product. v

6. The process of making white, lead, which comprises meltin lead, cpmminuting by means of an oxidizing fluid to make a filamented lead coated with catalytic oxid, treating such filamented lead as an integralprogressively advancing traveling stream with oxidizlng and carbonating agents in the presence of moisture until-carbonation is partially complete and in completing the carbonation while simultaneously increasing the temperature of the carbonating mass, said process-being conducted in a continuous and non-cumulative manner.

7: The process of making white lead,

which comprises melting lead and raisingv it to a supermolten condition, comminuting by the atomizing action of a pressure jet of heated air to make a'filamented lead coated with catalytic oxid, in treating said filamented leadas an integral progressivelyadvancing travelingst-ream, with oxidizing and carbonating moisture, in completing the carbonation while subjecting the traveling stream to an increase of temperature, and in drying the product, said process-being conducted in a continuous and non-cumulative manner. a 8. Apparatus for making white lead, comprising a kettle for meltmg metallic lead, means for discharging the molten v lead i'there'from as a thin stream, means for impinging thereon a comminuting fluid jet, a series of conveyers of'great length, for propelling the comminuted product as an integral'progressively advancing stream and means forlintro'ducing into sald conveycrs acurrent of air 7 andicarbon' dioxid.

' whereof I have aflixed mya I CARLETON Witnesses; Y Na "mm; L. Fo'smn,

JOHN H. DERBY,

agents in the presence of; 

